Na_2SeO_4对蛹虫草子实体生长的影响

蛹虫草是一种药食两用真菌,具有与冬虫夏草相似的功能,且富硒能力较强。本研究通过大量的人工栽培试验,旨在探究不同浓度Na_2SeO_4对新疆本地蛹虫草子实体生长的影响。试验表明,质量浓度为20 mg/L的Na_2SeO_4对蛹虫草的生长不产生显著影响,但蛹虫草各项生物学指标均随着培养基中外源Na_2SeO_4浓度的增加而呈下降趋势,说明随着外源Na_2SeO_4浓度的增加会对蛹虫草的生长产生抑制效应,当外源Na_2SeO_4质量浓度达到200 mg/L时,生产的蛹虫草已不具备商品价值。由此可见,20 mg/L的质量浓度是以Na_2SeO_4为硒源进行蛹虫草富硒研究的安全浓度。该研究为富硒产品开发寻找新的硒源开辟了新思路,为新疆地区进一步大规模栽培富硒蛹虫草提供一定的参考,但是对以Na_2SeO_4为硒源的最佳富硒浓度还有待于进一步研究。     

虫草多糖治疗家犬夹闭肾动脉引起的急性肾衰

探讨了虫草多糖对家犬夹闭肾动脉造成的急性肾衰的治疗作用。将实验动物家犬分为假手术组、阴性模型组、阳性组、虫草多糖高、中、低三个剂量组,观察治疗后犬的肾功能、血液生化指标、尿常规、肾脏病理的变化。发现虫草多糖组肾功能受损程度明显轻于阴性模型组（P〈0．01）,肾脏病理损伤明显减轻。实验证明虫草多糖能够治疗肾缺血诱发的急性肾功能衰竭,其机理可能与改善肾功能、增加肾血流量、纠正代谢紊乱、促进肾小管的修复与再生等作用有关。     

布莱克韦尔虫草的生物活性评价及其子实体的人工培育

虫草在世界范围内广泛分布,具有多种生物活性及较高的食药用价值。为进一步丰富虫草真菌资源,本研究对从广东韶关丹霞山采集到的一份野生虫草样品进行了菌株的分离鉴定、生物活性评价和子实体的诱导培养。通过形态学和系统发育分析,将菌株ZYJ0835鉴定为布莱克韦尔虫草Cordyceps blackwelliae。利用5种不同的培养基进行液体发酵培养,发现该菌株的发酵上清液和菌丝体均具有抗氧化和纤溶活性。此外,该菌株还具有一定的抑菌活性。利用大米、小麦、柞蚕蛹3种培养基质,均成功诱导出子实体,并且人工培养的子实体也具有抗氧化和纤溶活性。本研究首次在中国境内报道布莱克韦尔虫草的分布,为进一步开发利用该虫草资源提供了理论依据。     

Optimization of submerged culture requirements for the production of mycelial growth and exopolysaccharide by Cordyceps jiangxiensis JXPJ 0109

AIMS: The objective of the present study was to investigate the optimal culture requirements for mycelial growth and exopolysaccharide production by Cordyceps jiangxiensis JXPJ 0109 in submerged culture. METHODS AND RESULTS: The effects of medium ingredients (i.e. carbon and nitrogen sources, and growth factor) and other culture requirements (i.e. initial pH, temperature, etc.) on the production of mycelia and exopolysaccharide were observed using a one-factor-at-a-time method. More suitable culture requirements for mycelial growth and exopolysaccharide production were proved to be maltose, glycerol, tryptone, soya bean steep powder, yeast extract, medium capacity 200 ml in a 500-ml flask, agitation rate 180 rev min(-1), seed age 4-8 days, inoculum size 2.5-7.5% (v/v), etc. The optimal temperatures and initial pHs for mycelial growth and exopolysaccharide production were at 26 degrees C and pH 5 and at 28 degrees C and pH 7, respectively, and corresponding optimal culture age were observed to be 8 and 10 days respectively. According to the primary results of the one-factor-at-a-time experiments, the optimal medium for the mycelial growth and exopolysaccharide production were obtained using an orthogonal layout method to optimize further. Herein the effects of medium ingredients on the mycelial growth of C. jiangxiensis JXPJ 0109 were in the order of yeast extract > tryptone > maltose > CaCl2 > glycerol > MgSO4 > KH2PO4 and the optimal concentration of each composition was 15 g maltose (food-grade), 10 g glycerol, 10 g tryptone, 10 g yeast extract, 1 g KH2PO4, 0.2 g MgSO4, and 0.5 g CaCl2 in 1 l of distilled water, while the order of effects of those components on exopolysaccharide production was yeast extract > maltose > tryptone > glycerol > KH2PO4 > CaCl2 > MgSO4, corresponding to the optimal concentration of medium was as follows: 20 g maltose (food-grade), 8 g glycerol, 5 g tryptone, 10 g yeast extract, 1 g KH2PO4, and 0.5 g CaCl2 in 1 l of distilled water. CONCLUSIONS: Under the optimal culture requirements, the maximum exopolysaccharide production reached 3.5 g l(-1) after 10 days of fermentation, while the maximum production of mycelial growth achieved 14.5 g l(-1) after 8 days of fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on the submerged culture requirements for mycelial growth and exopolysaccharide in C. jiangxiensis, and this two-step optimization strategy in this study can be widely applied to other microbial fermentation processes.     

Hot-water extract from mycelia of Cordyceps sinensis as a substitute for antibiotic growth promoters

Broiler chicks were orally dosed with a hot-water extract of mycelia from Cordyceps sinensis (CS-HW) to assess possible substitution of Avilamycin as an antibiotic growth promoter (AGP). The growth performance (body weight gain and survivability) and the health index (the microflora in the small intestines and the antibody titer to Newcastle disease virus) of chicks were significantly improved in the CS-HW (600 mg/kg diet) and the Avilamycin (20 mg/kg diet) fed group in comparison with the control group (p<0.05). The Avilamycin-fed group and the CS-HW-fed group had similar growth performances but the latter gave a better microbial flora in the small intestines. These results indicate that CS-HW enhances the physiological activity in chicks and can be used as a substitute for AGPs.     

四种子囊菌甲醇提取物的抗氧化活性研究

比较了冬虫夏草Cordyceps sinensis、古尼虫草Cordyceps gunnii、蛹虫草Cordyceps militaris、黑柄炭角菌Xylaria nigripes等四种子囊菌提取物的抗氧化活性,对它们的子实体(F)和菌丝体(M)甲醇提取物清除DPPH自由基能力、还原力、金属离子鳌合能力和总酚含量进行了测定,结果显示四种子囊菌子实体的自由基清除能力、还原力和总酚含量均高于其菌丝体(P0.05),但四种子囊菌子实体的DPPH清除能力不存在显著差异(P0.05);古尼虫草和蛹虫草子实体的还原力和总酚含量显著高于冬虫夏草和黑柄炭角菌子实体(P0.05),但前两者之间不存在显著差异(P0.05)。总酚含量和DPPH自由基清除能力、还原力呈正相关。     

A new approach for improving cordycepin productivity in surface liquid culture of Cordyceps militaris using high‐energy ion beam irradiation

Aims: To obtain a higher cordycepin production using Cordyceps militaris mutant obtained by a new mutagenesis technique called ‘ion beam’. Methods and Results: Successful irradiation of C. militaris NBRC 9787 by a proton beam with high energy was performed, and 30 classes of 8‐azaadenine‐ and 28 classes of 8‐azaaguanine‐resistant mutants were obtained on mutant screening, of which seven classes were selected as promising preliminary mutants having an antibacterial ability as an index of cordycepin production. In a surface liquid culture technique, some of the 8‐azaadenine‐resistant mutants gave a better performance for the cordycepin productivity; in contrast, among the 8‐azaaguanine‐resistant mutants, it was shown that mutant no. G81‐3 was much better than the control in the metabolic rate of glucose and the cordycepin productivity. In primary optimization using the enriched medium, the cordycepin production was 3·1 and 1·8 g l^?1 on 21‐day culture for mutant no. G81‐3 and the control, respectively. The cordycepin production obtained by the mutant was 72% more than the control. Conclusions: The mutant obtained by proton beam irradiation had higher productivity of cordycepin than that of the control. Significance and Impact of the Study: The mutant obtained by irradiation had a superior production performance of cordycepin, and therefore, it could be used in the realm of applied industrial biotechnology for the large‐scale production of cordycepin.     

Immunomodulatory effect of exo-polysaccharides from submerged cultured <Emphasis Type="Italic">Cordyceps sinensis</Emphasis>: enhancement of cytokine synthesis,CD11b expression,and phagocytosis

Cordyceps sinensis is widely used as a traditional medicine for treatment of a wide variety of diseases or to maintain health. The immunomodulatory activity of polysaccharides prepared from submerged cultured C. sinensis BCRC36421 was investigated in human peripheral blood. Results demonstrated that Fr. A (exo-polysaccharides, 0.025 ∼ 0.1 mg/ml) induced the production of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-10 dose-dependently. Fr. A, as low as 0.025 mg/ml, could significantly augment surface expression of CD11b in monocytes and polymorphonuclear neutrophils. Functional assay revealed that Fr. A (0.05 mg/ml) also elevated phagocytosis in monocytes and PMN. On the other hand, Fr. B (intracellular polysaccharides) only moderately induced TNF-α release, CD11b expression, and phagocytosis at the same concentrations. Our results indicate that the immunomodulatory components of submerged cultured C. sinensis mainly reside in the culture filtrate.     

Effects of ammonium feeding on the production of bioactive metabolites (cordycepin and exopolysaccharides) in mycelial culture of a Cordyceps sinensis fungus

AIMS: To examine the effects of ammonium feeding on the production of cordycepin (3'-deoxyadenosine, a nucleoside analogue) and exopolysaccharides (EPS) in mycelial culture of a new Cordyceps sinensis fungus Cs-HK1. METHODS AND RESULTS: Cs-HK1 fungus was cultivated in a liquid medium containing glucose, yeast extract, peptone and a few major inorganic salts. NH(4)Cl was fed to the mycelial culture at various concentrations from 5 to 40 mmol l(-1) on day 3 (during exponential phase). NH(4)Cl, fed at 10 mmol l(-1), stimulated the cordycepin production most significantly, with nearly fourfold increase in the cordycepin content of mycelia (from 28.5 to 117 microg g(-1)), and also increased the EPS production by 40% (from 2.6 to 3.7 g l(-1)). The ammonium feeding had a slightly positive effect at 5-10 mmol l(-1), but a negative effect at higher concentrations on the mycelium growth. Ammonium feeding also caused a sharp drop of the medium pH, owing perhaps to the uptake of NH(3) and the release of H(+) by the fungal cells. CONCLUSIONS: Ammonium feeding to the mycelial culture of Cs-HK1 fungus enhanced the intracellular cordycepin accumulation and the EPS production. The enhanced cordycepin production may be attributed to the uptake of ammonia for nucleoside synthesis, and the enhanced EPS to the increased uptake of glucose for EPS biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: It is useful for the production of bioactive metabolites and for understanding ammonium metabolism and its relationship to the biosynthesis of nucleosides in a precious medicinal fungus.     

蛹虫草原生质体紫外诱变选育胞外多糖高产菌株

蛹虫草是重要的药食兼用两用真菌,具有较高的医用及经济价值。本文通过单因素和正交试验的方法研究了不同酶系统、酶解温度、酶解时间、渗透压稳定剂、菌龄对蛹虫草原生质体形成的影响,并对蛹虫草原生质体进行紫外诱变,以生物量和胞外多糖产量为指标选育胞外多糖高产菌株。结果表明：在30℃、1％溶壁酶＋0．5％蜗牛酶＋0．5％纤维素酶条件下,以甘露醇为渗透压稳定剂对4日龄蛹虫草菌丝酶解2h,原生质体产量可达到9．2×10^6个/mL。从150株诱变株中筛选出1株最佳正诱变株,编号为44#,经深层培养其生物量比出发菌株提高10％,胞外多糖产量提高84．3％,继代培养10代后,遗传稳定性良好。